Tube shield and base assembly



Aug. 1960 L. R. WOODS 2,951,108

TUBE SHIELD AND BASE ASSEMBLY Filed April 23, 1956 5 V 26 Zita 44, 14 71 000: a 1

United States Patent filice 2,951,108 Patented Aug. 30, 1960 tional Electronic Research Corporation, Los Angeles,

Calif a corporation of California Filed Apr. 23, 1956, Ser. No. 580,015

1 Claim. (Cl. 174-35) The invention relates to tube shields and has special reference to parts constituting a base and a shield for attachment thereto under circumstances where the shield or envelope portion of the assembly may be specially equipped to hold the glass bulb of the tube in some specified manner.

After it was discovered that for certain purposes an advantage exists in enclosing electronic tubes in a metallic shielding envelope for a long time the shielding constituted no more than use of a cylindrical sheet metal envelope pressed into position around the tube and socket and somewhat loosely attached to an anchoring means on the chassis. Recent developments, however, have emphasized the advantages and necessity for not only shielding the tube against the passage of' radio waves of certain frequencies but also, and more especially, for the purpose of conducting heat away from the glass bulb without inducing temperature cracks therein and also for improving the mounting of the electronic tube, thereby to minimize deteriorating effects which may result from use of the tubes in locations where sustained high frequency vibration effects might be present.

Construction of tube shields or tube shield envelopes to satisfy needs of this nature has been found incomplete where resort might be had to bases of conventional design for retention of the shielding envelope. Unless the connection between the base and the envelope has a heatconducting character comparable to the heat-conducting faculties of the shield assembly, many of the advantages of the latter are nullified. Also, if the shielding envelope is to be effective in minimizing the effects of high frequency vibrations, the connection between the tube shielding envelope and the base must be one capable of maintaining a sustained snug connection under such circumstances.

It is therefore among the objects of the invention to provide a new and improved tube shield and base assembly which is simple in construction and which at the same time is positive in its attachment, thereby to satisfactorily conduct heat through the junction.

Another object of the invention is to provide a new and improved tube shield and base assembly which provides a firm grip of one with respect to the other and which is sufficiently rugged and permanent to maintain its action under conditions where high frequency vibrations might exist.

Still another object of the invention is to provide a new and improved tube shield base which is sufficiently simple as to permit fabrication from sheet metal and which is so formed that it is rigid, durable, and capable of securing and maintaining a positive grip upon a tube shield envelope mounted thereon.

Still further among the objects of the invention is to provide a base for a tube shield envelope and an envelope for connection therewith, both of which are relatively simple and inexpensive sheet metal parts so constructed that they can be quickly engaged one with respect to the other, thereafter to maintain the engagement but which when necessary can be easily disengaged for facilitating removal and replacement of the tube within the shield.

With these and other objects in view, the invention consists in the construction, arrangement and combination of the various parts of the device whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claim and illustrated in the accompanying drawings.

The invention herein disclosed and claimed is a continuation-in-part of co-pending application Serial No. 345,597, filed March 30, 1953, now Patent No. 2,807,- 659.

In the drawings:

Figure l is a longitudinal sectional view of the tube shield and base assembly shown in position around a conventional electronic tube and socket therefor.

Figure 2 is an exploded perspective view of the tube shield envelope and base in the relative positions they would have prior to engagement.

Figure 3 is a perspective exploded view of a second form of the device.

Figure 4 is a fragmentary elevational view of connecting elements of the base and shield of Figure 3 shown prior to connection.

Figure 5 is a view similar to Figure 4 but showing the elements connected.

Figure 6 is a longitudinal sectional view taken on the line 6-6 of Figure 5.

In an embodiment of the invention chosen for the purpose or" illustration there is shown a chassis 1t} mounting a retainer 1i to which a socket 12 is attached. An electronic tube is mounted in the socket and a glass bulb 13 of the tube extends upwardly out of the socket.

The tube shield and base assembly comprises in the main two separate parts, namely, a base indicated generally by the reference character 16 and a tube shield device indicated generally by the reference character 17. For purposes of illustration the tube shield is illustrated as one containing a liner having a plurality of spring-like contact elements 18 which create a spring contact between the bulb 13 and the tube shield 17. The tube shield proper may appropriately be described as a cylindrical envelope. A flange 19 at the top of the envelope has an overhanging portion adapted to retain beneath it a spring 20 for pressing upon the outer end of the bulb. The base 16 comprises an outwardly extending flange 21 having holes 22 through which screws or rivets 23 may be extended to secure the base to the chassis 10. A cylindrical collar extends upwardly from the flange and at the top of the collar is a series of four tabs 25, 26, 27 and 28. The tabs are identical in each instance and each includes an inwardly projecting lip 29 tilted at an oblique angle, as shown to good advantage in Figure 2.

The tube shield or envelope 17 has four corresponding base gripping portions 30, 31, etc., each portion in turn including a laterally open, obliquely disposed slot 32 matching in obliquity the lips 29. A short finger element 33 underlies the slot and a long finger element 34 lies over the slot. Tab-receiving spaces '35 are provided for by the short finger element having a width more than suflicient to receive any one of the tabs 25, 26, etc. By having the diameter of the shield or envelope 17 at its lower end substantially equal to the inside diameter of the collar 24, or in fact by having the basegripping portions extended very slightly, they can be sprung inwardly when the envelope is pressed downwardly inside of the collar and the outer surfaces of the envelope will therefore be in snug engagement with the inside wall of the collar. When the envelope is applied to the base, the base-gripping portions are pushed within the collar and the spaces 35 extended over the tabs and the inwardly extending lips 29. The envelope is then rotated slightly less than 90 degrees and the lips slide down the oblique slots 32 to the bottoms of the slots where they are maintained partly bythe expanding resilience of the lower end of the envelope and in part by the action of spring 20 which tends to force the envelope outwardly relative to the base. Windows 36 assist in passing heat by radiation from the glass bulb to the eX-' terior.

In a second form of the invention illustrated in Figures 3, 4, and 6 there is shown an envelope 40 which may consist of a single metal stamping continuous throughout its perimeter, on the upper end of which is a flanged ring 41. Windows 42 may be provided if needed for facilitating the escape of heat through the envelope.

At a base end of the envelope is a plurality of basegripping portions 43, on one side of which is a slot 44, below which is a short finger element 45, and above which is a long finger element 46. A base indicated generally by the reference character 47 has a flange 48 adapted to be secured to a chassis 49 by means of screws or rivets 50. A collar 51 extends upwardly of the flange 48 and at the upper rim of the collar are inwardly extending tabs 52, each tilted at an oblique angle corresponding to the obliquity of the slots 44. Adjacent open ends of the slots are spaces 55 materially wider at the narrow end than the length of the tabs 52 and being progressively wider toward the open end. Sloping sides 56 and 57 assist in guiding the envelope to its position with respect to the tabs 52. After the envelope has been pushed downwardly until the tabs engage bottoms 58 of the spaces 55, the envelope is rotated, and, the tabs being at the same angular pitch in the slots, a snug engagement is readily accomplished.

There has accordingly been disclosed herein a tube shield envelope and base'assembly which is sufficiently simple in design to be capable of being fabricated by stamping from light gage sheet metal and which by reason of the relationship of the parts provides an easily connectable firm grip between the envelope and base tight enough for the transfer of heat by conduction and secure 2,951,108 I A r 4 enough to withstand disturbance by the presence of high frequency vibrations.

While I have herein shown and described my invention in what I have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of my invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claim so as to embrace any and all equivalent devices.

Having described my invention, what i claim as new and desire to secure by Letters Patent is:

A tube shield assembly for application over an electronic tube comprising; a substantially cylindrical base adapted to be mounted in an upright position on a chassis, said base having a plurality of circumferentially spaced inturned tabs at its upper edge, a shielding tube and retaining envelope comprising a sheet metal cylinder having an inturned flange at its upper end, a spring inside said shielding tube, bearing against said flange and adapted to press against an electronic tube to urge said shielding tube upwardly, the lower end of said shielding tube being of a diameter to be snugly received within said base and being provided with a plurality of downwardly open notches corresponding to said tabs on said base and of a size to readily receive the same, a slot extending helically from the uppermost portion of each notch and adapted to receive a corresponding tab, each of said slots extending helically downwardly toward but short of the lower end of said shielding tube.

References Cited in the file of this patent UNITED STATES PATENTS 337,867 Richards Mar. 16, 1886 831,224 Hammer Sept. 18, 1906 2,367,458 Coplen Jan. 16, 1945 2,646,460 Del Camp July 21, 1953 FOREIGN PATENTS 11,284 Great Britain May 25, 1908 of 1908 649,059 Great Britain Jan. 17, 1951 

